Invasive zombie plant takes hold in St. John River

When aquatic botanist Meghann Bruce found an invasive species nicknamed zombie plant in the St. John River in 2015, she only found it in one spot. 

She actually stumbled upon Eurasian watermilfoil while doing a botanical survey of the river for another project. 

As part of that study, she explored 171 sites between the Mactaquac Dam and the Princess Margaret Bridge in Fredericton. 

She returned to the same sites in 2018 and discovered the invasive plant in more than 60 of the locations. 

Bruce hasn't checked all of those sites since then, but she's regularly on the water in those areas and suspects the Eurasian watermilfoil has spread even further. 

"It's not that surprising because it is an invasive species and one thing that they tend to have is a broad environmental tolerance, and so they tend to grow really well in new areas that they're introduced to."

As with many invasive species, now that Eurasian watermilfoil has established itself in the river system, "eradication is not feasible," said Bruce. 

One local group, however, isn't willing to go down without a fight. 

The Jemseg Grand Lake Watershed Association launched a pilot project last year to try to keep the plant at bay. The goal is to slow the spread and reduce the number of plants in some heavily affected areas. 

Last fall, the team divided an affected area into three zones, explained project co-ordinator Juan Sanchez. 

In one, they used scissors to snip off the plants at ground level. In another, they pulled up the plants by hand — roots and all. And the third area was left alone as a control site. 

In the first two areas, they removed all of the zombie plants and anything that looked like them, including native watermilfoils, just to be sure they got it all. 

Sanchez returned to the area this year and counted every single plant in all three sites.

Where they snipped the intruders with scissors, he found 30-40 plants — roughly the same number found last year — but where they pulled the plants by the roots, there were only five to 10.